Well, that thing is freaky.
We are kinda in an awkward position here.
Yulia however, should absolutely dominate since the enemy uses almost only ranged weapons. The only danger is the Officer getting close with his stun attack and whatever the cell have in store for us.
Going into a cell might actually be the best play here, we could use Yulia to block the door, thus forcing the enemy to come at us in close combat.
I would say Maple and Lri should secure one of the cells by tossing an EMP in and blasting everything that moves while Yulia takes the attention of the Officer and his goons. The goons would either have to come down from the walkway or be rendered useless. If they do give chase, Yulia should join Lri and Maple in the cell.
From there we can blast the enemy with concentrated fire and EMP's
The only danger I see is if the Officer could lock the cell automatically, but we do have masterful unlock, so I think we could break out easily enough if that were to happen.
Other then that, I think Emmie's array of spells is fine, although I would add Force Lance in the mix too.